Guiding comb for picking the weft by a stream of gaseous pressure medium

ABSTRACT

A guiding comb for shuttleless looms for picking the weft thread into the shed of the loom, having teeth which can be adjusted in two angular positions, in the first one where the picking openings of the teeth form a practically completely closed channel, and in a second one, where gaps are created between adjacent teeth, enabling their entrance into and removal from the system of warp threads forming the shed.

States Patent 1191 Cernoeky et al.

1451 Aug. 13,1974

[ GUIDING COMB FOR PICKING THE WEFT BY A STREAM OF GASEOUS PRESSUREMEDIUM Inventors Jiri Cernocky; Miloslav Riha, both 1 of Rybniky; JosefMartinec, Luh, all

of Czechoslovakia Zbojovka Vsetin Narodni, Vsetin, Czechoslovakia Filed:Feb. 22, 1972 Appl. No.; 227,875

Assignee:

Foreign Application Priority Data Oct. 2, I970 Czechoslovakia 667870 US.Cl. 139/127 P Int. Cl D03d 47/30 Field of Search 139/127 R, 127 P, 188

llllll lllll References Cited UNITED STATES PATENTS. 3,124,167 3/1964Strake 139/127 P 3,557,345 1/1971 Svaty etal 139/127 P 7 PrimaryExaminer-Henry S. Jaudon [5 7] ABSTRACT A guiding comb for shuttlelesslooms for picking the weft thread into the shed of the loom, havingteeth which can be adjusted in two angular positions, in the first onewhere the picking openings of the teeth form a practically completelyclosed channel, and in a second one, where gaps are created betweenadjacent teeth, enabling their entrance into and removal from the systemof warp threads forming the shed.

3 Claims, 5 Drawing Figures GUIDllNG COMB FOR PICKING THE WEFT BY ASTREAM OF GASEOUS PRESSURE MEDIUM BACKGROUND OF THE DISCLOSURE Theinvention relates to a guiding comb for picking a weft thread into theshed of a loom by a stream of a gaseous medium, the comb beingparticularly suitable for air jet looms.

In looms, where the weft thread is picked into the shed by a stream ofpressure air, this stream of pressure air has tovbe confined in order tobe able to pick the weft thread throughout the whole width of the shed.The arrangement confining the stream of pressure air taking along thepicked weft thread has to be designed so as to prevent to the utmost anystray losses of the gaseous medium in the course of its contact with thesurrounding air and thus to maintain its speed required for picking theweft thread. This requirement is particularly important for looms havinglarger reed-widths, where the weft thread has to be picked for a largerdistance from the mouth of the arrangement, performing the picking ofthe weft thread by a stream of a gaseous medium.

Guiding combs are therefore used atpresent, the individual teeth ofwhich engage between warp threads of an open shed, said teeth havingopenings for guiding the air stream. This arrangement substantiallycomplies I with the requirements of confining of the air stream and canbe advantageously usedfor looms having smaller widths of the reed. Adrawback is that gaps must be between the individual teeth in order toenable their penetration into the system of warp threads. in the courseof passage of the air stream taking along the picked in weft, thepressure air escapes through these gaps into the ambient space andsurrounding air is simultaneously sucked in. Both these circumstancescause a reduction of speed of the air streamand thus its capability toreliably pick the weft, particularly for looms having larger widths ofthe reed.

An arrangement is furthermore used, where the open shed is in the courseof picking coveredin its whole length by special cover plates, whichtogether withone side of the reed form a closed space of triangularcross section. The weft is introduced into this, triangular space fromone side by pressure air and is sucked on at the other side by anotheradditional device. The warp threads of the open shed are in this case ina closed space which represents a drawback of this arrangement. Duringthe picking of the weft into the shed by pressure air, the warp threadsstart to vibrate and thus braking or retarding the streaming air. If awarp thread should become loosened under these conditions, the picked inweft can be caught and cause a defect in the fabric.

According to another arrangement the weft is introduced by means theweft ofa hollow needle engaging up to the center of the open shed, whereit is taken over by a similar hollow needle entering the shed from theopposite side, by means of which the weft is gripped by being sucked onand brought across the other half of the shed. After the taking over ofthe weft by the second needle, both needles are removedfrom the openshed. This arrangement issomewhat complicated, can operate with reducedspeed only, and a further drawback is that such a loom needs asubstantially larger floor space. An arrangement for picking the weftinto the shed by means of a stream of pressure air .is also known, wherethis stream of pressure air is rectified by a special trough andcomplemented by additional pressure air,'suppliedby jets situated atcertain distances along the whole width of the-shed. These jets aredesigned and controlled so as to be able to penetrate in the course ofpicking into the system of warp threads and to confine by the producedair stream the weft in the trough. This method permits a relativelyreliable picking in the weft; much air is, however, dissipated and suchmethod requires large amounts'of air.

It is an object of this invention to provide a guiding comb pickingthrough the weft, which operates reliably, which eliminates the dangerof the weft being caught by loosened warp threads, which is economicalin air consumption and which may be used for larger widths of the shed.The teeth of the guiding comb according to this invention can beconsidered as parts of a hollow body, for instance of a cylinder, cutalong parallel planes inclined with respect to the longitudinal axis'ofthis hollow body at a chosen angle and having a chosen thickness. Eachindividual tooth is provided with a stem, the axis of which isperpendicular to the axis of the imaginary hollow body. The individualteeth are by means of their stems controlled by a device, operating toturn all teeth simultaneously to two operating positions. Thefundamental operating position of the tooth corresponds with the angleof the inclined cut of the imaginary hollow body, in the secondoperating position the teeth are turned perpendicularly to the axis ofthe imaginary hollow body to a position parallel with the warp threads.By turning the teeth, gaps are produced between the individual teeth,the magnitude of which depends on the chosen angle of the cut, inclinedwith respect to the axis of the imaginary hollow body. With the teeth inthis position it is possible to introduce them into the system of warpthreads in the course of opening of the shed,.whereby the warp threadscan pass through gaps between individual teeth of the guiding comb up toa moment where the teeth reach a position in front of the device forpicking through the weft by means of a gaseous medium. At that time theteeth are again turned into their original fundamental position, formingby their openings a substantially fully closed channel, whichefficiently confines the stream of gaseous pressure medium for pickingin the weft. After the weft has been picked in, the individual teeth ofthe guiding comb are again turned into a position corresponding to thedirection of warp threads and the teeth can be removed from the closingshed, whereby the picked weft, which has been in the picking openings ofthe teeth, is removed therefrom by way of exit slots provided in eachtooth. The picked weft is after removal from the teeth beaten up to thefabric by the reed and woven in by exchange of both systems of warpthreads. The internal walls of the picking openings of the teeth areafter turning into their fundamental position, where they form asubstantially completely dosed channel, substantially parallel with theaxis of the channel, enabling a picking in of the weft from one or theother side of the shed.

An advantage of the thus arranged teeth of the guiding comb is that thegaseous medium causing the direct picking in the weft is efficientlyrectified by the teeth and the speed of its passage is maintained withonly small losses of its volume. The space required for the deviceconfining the gaseous medium is small and the dimensions of the openshed may be also kept relatively small. A contact of the gaseous mediumwith the warp threads is impossible and no loosening and tearing up ofthese threads can be caused in the course of picking through the weft.The weft cannot be also caught by loose warp threads. The closed pickingopenings of the teeth form a tube with a smooth, non-converging, inside,enabling the weft to be picked alternately from one and then the otherside of the shed.

DESCRIPTION OF DRAWINGS The attached drawings show an examplaryembodiment of the arrangement of teeth of a guiding comb according tothis invention, Where FIG. 1 shows an elevation of a tooth of a guidingcomb in two operating positions A and B in the front and rear positionof the batten,

FIG. 1a is a fragmentary view partially in section and partially inelevation showing means for transmitting the swinging movement of thecrank to a linear reciprocatory movement of the rack which imparts apivotal movement to the teeth between two active positions thereof;

FIG. 2 is a top view of the teeth in their fundamental position A,

FIG. 3 is a top view of the teeth, turned to position B, where gaps arecreated between the teeth, enabling DESCRIPTION OF PREFERRED EMBODIMENTThe teeth 1 of the guiding comb are built substantially as parts of ahollow body, for instance of a cylinder, cut along parallel planesinclined with respect to the axis of this hollow body at an angle a andhaving a thickness s. (FIG. 2) Each tooth 1 has a stem 2, the axis ofwhich is preferably perpendicular to the axis of the imaginary hollowbody. The angular position of the teeth 1 is controlled by a mechanism 3composed, for instance, of a rack guided within the batten 4 and of camson the stems of the teeth, the whole arrangement being supported, forinstance, on the batten 4 and controlled by a crank 5 (FIG. 1). Thefundamental position A of the teeth 1 corresponds angularly to the anglea of the plane of the inclined cut of the imaginary hollow body (FIG.2). In this position the teeth 1 of the guiding comb form a continuoussubstantially closed channel 6 for confining the stream of the gaseousmedium in the course of picking the weft. At the moment prior to turningof the batten 4 with the reed 7 to the beating up position the teeth 1are turned to position B (FIG. 3), creating gaps between the individualteeth 1, enabling the entrance of the teeth of the guiding comb throughthe system of warp threads into the shed, or their removal from the shedafter the weft has been picked in.

The position B of the teeth 1 is advantageously parallel with the warpthreads 8. Immediately after entrance of the teeth into the shed, in thecourse of which movement the teeth finish by their flanks the separationof warp threads, even of those which are loosened and are hanging overinto the shed, an impulse is generated for turning the teeth to thefundamental position A creating a continuous closed channel 6, whichconfines the stream of gaseous medium taking along the weft after it hasleft the jet. After the weft has been picked in and after acorresponding impulse, the teeth 1 of the guiding comb are turned backto position B and the removal of the teeth 1 from the shed is started ata simultaneous removal of the picked in weft from the picking opening ofthe teeth by way of exit slots 9, which are preferably arranged so as tobe in position B of the teeth 1 (FIG. 3) in register and in a commonplane, parallel with the axis of picking of the weft in the shed. Duringa turn of the teeth 1 to position A the exit slots are mutually offset,so that the picking channel is closed and any slipping out of the weftfrom the channel in the course of the picking operation is prevented.

The embodiment shown herein operates in the following manner, referencebeing had specifically to FIGS. 1 and 1a. The swinging movement of thecrank 5 is transmitted via a connecting rod 10 to a sword 11, the sword11 being pivoted at 12 at one of its extremities and at the otherextremity being fixedly attached to the batten 4. A cam 13, the outerend of the crank arm, is connected to the connecting rod 10 by a pivotpin 14 which is fixedly connected to the connected rod. Mounted on anextension of the pivot pin 14 is a cam 13 which thus partially rotatesabout its axis in synchronism with the swinging movement of theconnecting rod 10. The cam 13 cooperates by means of a pin cam follower15 with an arm 16 of a two-arm lever 17 pivoted at 18. The arm 16 isconstantly urged counterclockwise (FIG. 1a) by a coil tension spring 19secured to a lug 30 on the body 21 which is fixed to the batten 4. Thesecond arm 22 of the two-arm lever 17 cooperates with the rack 23 which,due to its reciprocatory movement, imparts a pivotal movement to all thearms 24 projecting from the stems 2 of the respective teeth 1, also asshown in FIG. la.

We claim:

1. In a jet loom having a batten, and in which weft thread is picked bystream of a gaseous pressure medium through sheds formed in warpthreads, the improvement which comprises a comb mounted on said battenfor guiding a stream of gaseous pressure medium through successivesheds, the comb having teeth each of which is provided with a stem,means on the batten for pivotally supporting the stems of said teeth inalignment along the length of the batten, and means for synchronouslyturning all of the teeth about the axis of their stems from a firstterminal position in which the teeth lie transverse to the length of thebatten and present warp thread receiving slots therebetween therebypermitting their entrance into and their removal from the system of warpthreads forming the sheds in a loom, to a second terminal position inwhich the interfaces between successive teeth lie at acute angles withrespect to the length of the batten with adjacent interfaces being insubstantial interengagement, whereby the teeth form an elongatedsubstantially closed hollow body having a passage therethrough for thepicking of the weft.

2. Guiding comb as set forth in claim 1, the teeht having openingstherethrough, said openings in the second terminal position of the teethlying coaxial, the internal walls of the openings of the teeth in saidsecond terminal position forming a smooth and completely closed channelfor picking the weft.

3. Guiding comb as seth forth in claim 1, wherein the circumference ofeach of said teeth is interrupted by an exit slot for the removal of thepick weft thread, said slot so located that in said first terminalposition of the comb teeth said exit slots are in register, and in thesecond terminal position of the comb teeth said exit slots are offset.

1. In a jet loom having a batten, and in which weft thread is picked bystream of a gaseous pressure medium through sheds formed in warpthreads, the improvement which comprises a comb mounted on said battenfor guiding a stream of gaseous pressure medium through successivesheds, the comb having teeth each of which is provided with a stem,means on the batten for pivotally supporting the stems of said teeth inalignment along the length of the batten, and means for synchronouslyturning all of the teeth about the axis of their stems from a firstterminal position in which the teeth lie transverse to the length of thebatten and present warp thread receiving slots therebetween therebypermitting their entrance into and their removal from the system of warpthreads forming the sheds in a loom, to a second terminal position inwhich the interfaces between successive teeth lie at acute angles withrespect to the length of the batten with adjacent interfaces being insubstantial interengagement, whereby the teeth form an elongatedsubstantially closed hollow body having a passage therethrough for thepicking of the weft.
 2. Guiding comb as set forth in claim 1, the teehthaving openings therethrough, said openings in the second terminalposition of the teeth lying coaxial, the internal walls of the openingsof the teeth in said second terminal position forming a smooth andcompletely closed channel for picking the weft.
 3. Guiding comb as sethforth in claim 1, wherein the circumference of each of said teeth isinterrupted by an exit slot for the removal of the pick weft thread,said slot so located that in said first terminal position of the combteeth said exit slots are in register, and in the second terminalposition of the comb teeth said exit slots are offset.